Inductive heating systems and methods of controlling the same to reduce biological carryover

ABSTRACT

Inductive heating systems and method of controlling the same to reduce biological carryover are disclosed herein. An example system includes an induction heater including a tank circuit. The example system includes a controller to drive the tank circuit to selectively oscillate at a resonant frequency for the tank circuit to inductively heat a work piece disposed proximate to the tank circuit.

RELATED APPLICATION

This patent claims priority to U.S. Provisional Patent Application Ser.No. 62/438,250, which was filed on Dec. 22, 2016. U.S. Application Ser.No. 62/438,250 is hereby incorporated herein by reference in itsentirety.

FIELD OF THE DISCLOSURE

This disclosure relates generally to medical diagnostic instruments and,more particularly, to inductive heating systems and methods ofcontrolling the same to reduce biological carryover.

BACKGROUND

Aspiration and dispense devices such as pipettor probes are used withautomated medical diagnostic instruments to aspirate and/or dispensefluids such as biological samples (e.g., serum, urine) and/or reagentsas part of diagnostic testing procedures. Aspiration and dispensedevices can be reused to reduce waste and operational costs. However,reusing aspiration and dispense devices increases the probability ofintroducing biological carryover and/or contamination into subsequenttests.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of electromagnetic induction.

FIG. 2 is a block diagram of an example system for inductively heating awork piece constructed in accordance with teachings disclosed herein.

FIG. 3 is a block diagram of an example induction heater station of theexample system of FIG. 2.

FIG. 4 is a schematic illustration of an example circuitry that may beused with the example induction heater station of FIG. 3.

FIG. 5 is diagram illustrating an example temperature profile forinductively heating a work piece using the example system of FIG. 2.

FIG. 6 is a perspective view of an example inductive heating coil thatmay be used with the example system of FIG. 2.

FIG. 7 is a perspective view of an example electromagnetic inductionshield and an example heat sink for use in connection with the examplesystem of FIG. 2.

FIG. 8 is a top view of a first example wash cup for use in connectionwith the example system of FIG. 2.

FIG. 9 is a cross-sectional view of the example first wash cup takenalong the 1-1 line of FIG. 8.

FIG. 10 is a flow diagram of an example method for causing a tankcircuit to resonate at a natural frequency that can be used to implementthe examples disclosed herein.

FIG. 11 is a flow diagram of an example method for inductively heating awork piece that can be used to implement the examples disclosed herein.

FIG. 12 is a diagram of an example processor platform for use with theexamples disclosed herein.

The figures are not to scale. Instead, to clarify multiple layers andregions, the thickness of the layers may be enlarged in the drawings.Wherever possible, the same reference numbers will be used throughoutthe drawing(s) and accompanying written description to refer to the sameor like parts.

DETAILED DESCRIPTION

Automated medical diagnostic instruments such as clinical chemistryanalyzers can be used to analyze a biological sample (e.g., serum,urine) by performing one or more tests on the sample, such as animmunoassay. An aspiration and dispense device such as a pipettor probemay be used with the diagnostic instrument as part of, for example, anautomated pipetting system for transporting fluids within the instrumentsuch as the sample, one or more reagents, etc. For example, anaspiration and dispense device can be used to deliver and/or removefluids from reaction vessels of the instrument, move fluids betweenvessels, mix fluids, etc.

During use, at least a portion of the interior and/or exterior surfacesof the aspiration and dispense device are exposed to the fluids that theaspiration and dispense device transports. In some examples, residualmaterials associated with the sample and/or reagent, such as proteins orviral materials, may remain on the interior and/or the exterior surfacesof the aspiration and dispense device. As a result, subsequent use ofthe aspiration and dispense device can result in carryover of the sampleor the reagent, or the transfer of the sample or the reagent intoanother sample or reagent. Thus, reuse of the aspiration and dispensedevice can contaminate the sample and/or the regent exposed to theaspiration and dispense device in connection with subsequent uses of thedevice. The aspiration and dispense device can be cleaned in an effortto reduce carryover and/or contamination by sterilizing the deviceusing, for example, heat.

Example systems, methods, and apparatus disclosed herein useelectromagnetic inductive heating to clean a work piece such as anaspiration and dispense device. Examples disclosed herein include aninduction heater that can be integrated in and implemented by anautomated diagnostic instrument, such as a clinical chemistry analyzer,an immunoassay analyzer, etc. In some examples disclosed herein, theinstrument in which the induction heater is integrated provides power tothe induction heater, is used to control one or more settings of theinduction heater via a graphical user interface, etc. In some disclosedexamples, the induction heater includes an induction heating circuitincluding an electrically conducting media, such as a coil. Anelectrical current is provided to the electrically conducting media,which induces an electromagnetic field. In disclosed examples, the workpiece is disposed proximate to the electrically conducting media (e.g.,inserted in an opening in the coil) and heated via the magnetic field.In disclosed examples, heating the aspiration and dispense devicesubstantially removes and/or alters one or more properties of thematerial remaining on the aspiration and dispense device so as tosubstantially reduce the probability of carryover and/or contaminationwith subsequent use of the aspiration and dispense device.

In some disclosed examples, a wash fluid is applied to the work piecebefore, during, and/or after inductively heating the work piece to rinsethe biological and/or chemical materials from the surfaces of thedevice. Some disclosed examples include a wash cup to collect the washfluid. In some disclosed examples, the electrically conducting media isdisposed proximate to the wash cup, and in some examples, is removablysecured to a portion of the wash cup to facilitate collection of thewash fluid during inductive heating of the work piece.

In examples disclosed herein, the induction heating circuit includestank circuit including a first coil to serve as an electricallyinducting media for heating the work piece. In some disclosed examples,a second coil is wound around the first coil to sense an oscillatingmagnetic field generated by the first coil and to synchronize electricalcurrent provided to the tank circuit with current already flowingthrough first coil. In examples disclosed herein, signals correspondingto the oscillating magnetic field generated by the first coil aredynamically detected by the second coil. The signals are used to drivethe electrical current provided to the tank circuit such that the tankcircuit is driven at its resonant frequency rather than a fixedfrequency. Driving the tank circuit at its resonant frequency reducesenergy losses and provides for an increased amount of energy to betransferred to the aspiration and dispense device heated by the firstcoil as compared to driving the tank circuit at a fixed frequency. Thus,disclosed examples improve efficiency of the inductive heating of theaspiration and dispense device. Driving the tank circuit to resonate atits natural frequency also compensates for manufacturing variabilitywith respect to components such as coils and capacitors. Driving thetank circuit to resonate at its natural frequency also accommodatesdynamic load variabilities with respect to changes in the resonantfrequency of the tank circuit due to the introduction of work pieceshaving different diameters, skin thickness, etc. into the magneticfield.

In some disclosed examples, the electrically conducting media of theinduction heating circuit (e.g., the coil) is coated with one or morematerials to prevent corrosion from biological and chemical interactionsbetween the work piece, the wash fluid, and the electrically conductingmedia. Some disclosed examples detect and/or predict failure of one ormore components of the induction heater by monitoring performance dataof the heater such as voltage, current, and frequency. Also, somedisclosed examples include a heat sink to reduce a risk of overheatingof the coil and a printed circuit board on which components such ascapacitors of the tank circuit are mounted. Thus, disclosed examplesprovide stable and reliable means for inductively heating and aspirationand dispense device.

An example system disclosed herein includes an induction heaterincluding a tank circuit. The example system includes a controller todrive the tank circuit to selectively oscillate at a resonant frequencyfor the tank circuit to inductively heat a work piece disposed proximateto the tank circuit.

In some examples, the controller is to drive the tank circuit toselectively oscillate at the resonant frequency based on a property ofthe work piece.

In some examples, the controller is to drive the tank circuit toselectively oscillate between the resonant frequency and a fixedfrequency.

In some examples, the tank circuit includes a work coil and a sensecoil. In such examples, the sense coil is to be wound around the workcoil.

In some examples, the controller is to drive the tank circuit tooscillate at the resonant frequency based on a signal generated by thesense coil.

In some examples, the system further includes a heat sink coupled to theinduction heater.

In some examples, the system further includes a shield including athermally conductive material coupled to the induction heater.

In some examples, the tank circuit includes a work coil, the work coilto be disposed in a wash cup. In some such examples, the work piece isto be exposed to fluid during the inductive heating. In some suchexamples, the fluid is to undergo a phase change during the inductiveheating.

In some examples, the controller is to access at least one oftemperature data, current data, or voltage data from the inductionheater. In such examples, the controller is to predict a performancecondition of the induction heater based on the data.

In some examples, the work piece includes a first portion and a secondportion. In such examples, the controller to selectively adjust a heatsetting at the tank circuit for the first portion and the secondportion. In some such examples, the controller is to adjust the heatsetting for the first portion based on a first temperature profile forthe first portion and adjust the heat setting for the second portionbased on a second temperature profile for the second portion.

An example method disclosed herein includes providing, by executing aninstruction with a processor, a current to an induction heater, theinduction heater including a tank circuit. The example method includesdriving, by executing an instruction with the processor, the tankcircuit to selectively oscillate at a resonant frequency for the tankcircuit. The example method includes inductively heating a work piecedisposed proximate to the tank circuit.

In some examples, the driving of the tank circuit to selectivelyoscillate at the resonant frequency is to be based on a property of thework piece.

An example tangible computer-readable medium disclosed herein includesinstructions that, when executed, cause a processor to at least providea current to an induction heater, the induction heater including a tankcircuit. The instructions cause the processor to drive the tank circuitto selectively oscillate at a resonant frequency for the tank circuit toinductively heat a work piece disposed proximate to the tank circuit.

In some examples, the instructions, when executed, further cause theprocessor to drive the tank circuit to selectively oscillate at theresonant frequency based on a property of the work piece.

In some examples, the instructions, when executed, further cause theprocessor to drive the tank circuit to selectively oscillate between theresonant frequency and a fixed frequency.

In some examples, the work piece includes a first portion and a secondportion, and the instructions, when executed, further cause theprocessor to selectively adjust a heat setting at the tank circuit forthe first portion and the second portion.

In some examples, the instructions, when executed, further cause theprocessor to adjust the heat setting for the first portion based on afirst temperature profile for the first portion and adjust the heatsetting for the second portion based on a second temperature profile forthe second portion.

Turning now to the figures, FIG. 1 is a schematic illustration ofelectromagnetic induction. As shown in FIG. 1, at least a portion of awork piece 100 to be heated (e.g., an aspiration and dispense device) isremovably disposed in an electrically conducting media such as, forexample, a coil 102. In the example of FIG. 1, the work piece 100includes a metal. An alternating current is provided to the coil 102(e.g., from a current source) and flows through the coil 102, asrepresented by arrows 104 in FIG. 1. The alternating current flowingthrough the coil 102 induces a magnetic field 106 in an area around thecoil 102. The magnetic field 106 induces eddy currents the work piece100, as represented by the arrows 108 in FIG. 1. The eddy currentsgenerate localized heat that raises the temperature of the work piece100 without direct contact between the work piece 100 and the coil 102.In examples where the work piece 100 is an aspiration and dispensedevice, the heat can affect properties of one or more materials (e.g.,residual biological materials) on the interior and/or exterior surfaceof the work piece 100 to enable the materials to be removed or alteredand the work piece 100 to be cleaned.

FIG. 2 is a block diagram of an example system 200 to reduce biologicalcarryover via inductive heating. The example system 200 includes adiagnostic instrument 202. The diagnostic instrument 202 can be, forexample, clinical chemistry analyzer, an immunoassay analyzer, etc. Theexample diagnostic instrument 202 includes a processor 204 to controlone or more functions performed by the instrument 202, such asmanipulating test samples, performing readings of the test samples,positioning reaction vessels, delivering fluids to and/or removingfluids from the reaction vessels, etc. The example diagnostic instrument202 includes a power source 206. The power source 206 can include, forexample, a battery, an electrical outlet, etc. The example diagnosticinstrument 202 includes a display 208. The display 208 can present oneor more graphical user interfaces (GUIs) 209 to a user of the diagnosticinstrument 202 to, for example, receive user inputs via the GUI(s) 209,display analysis results via the GUI(s) 209, etc. The diagnosticinstrument 202 can include a timer 211 to monitor, trigger, or moregenerally provide timing control of one or more functions performed bythe diagnostic instrument 202 with respect to analyzing a sample.

In the example system 200 of FIG. 2, the diagnostic instrument 202includes an induction heater control station 210. The example inductionheater control station 210 includes an induction heater 212 to clean orsterilize a work piece 214 (e.g., the work piece 100 of FIG. 1) viainductive heating as substantially disclosed in connection with FIG. 1.The work piece 214 can include an aspiration and dispense device thatmay be used to perform one or more functions with respect to experimentsand/or analyses performed by the diagnostic instrument 202, such astransporting a biological sample, delivering a reagent, etc. As a resultof the use of the work piece 214 with the diagnostic instrument 202, thework piece 214 may include biological and/or chemical material residueon one or more surfaces of the work piece 214 such that re-use of thework piece 214 could contaminate other samples and/or reagents.

The work piece 214 can include one or more portions having differentproperties 215 with respect to, for example, skin thickness, diameter,cross-section shape, material, etc. The properties 215 of the work piece214 can affect magnetic properties of the work piece 214 with respect toheating the work piece 214 via a magnetic field. For example, asillustrated in FIG. 2, the work piece 214 can include a first portion217 having a first diameter and a second portion 219 having a seconddiameter smaller than the first diameter. In some examples, the workpiece 214 is moved relative to the induction heater 212 via, forexample, a robotic arm 221 of the diagnostic instrument 202 so as toselectively heat and clean the first portion 217 and the second portion219 of the work piece 214. The work piece 214 can include additional orfewer portions than illustrated in FIG. 2. In some examples, the workpiece 214 is a probe including an opening defined by and extendingthrough the portions 217, 219 of the work piece.

In the example of FIG. 2, the induction heater 212 is disposed proximateto a wash cup 216. In some examples, the induction heater 212 is coupledto the wash cup 216. For example, the induction heater 212 can becoupled to an interior of the wash cup 216. In the example of FIG. 2, atleast a portion of the work piece 214 is disposed in the wash cup 216.In some examples, the work piece 214 is rinsed with fluid 218 (e.g., aliquid) before, during, and/or after being heated via the inductionheater 212. The wash cup 216 collects the fluid 218.

The example induction heater control station 210 of FIG. 2 includes apower drive unit 220. In the example of FIG. 2, the power source 206 ofthe diagnostic instrument 202 provides power (e.g., in the form ofdirect current (DC)) to the power drive unit 220, as represented byarrow 222 of FIG. 2. The power received by the power drive unit 220 fromthe power source 206 is used to drive the induction heater 212 via drivesignal(s), as represented by arrow 224 of FIG. 2. In some examples, thepower drive unit 220 includes a DC-to-DC converter to convert the DCreceived from the power source 206 from one voltage level to anothervoltage level.

The example induction heater control station 210 of FIG. 2 includes aninduction heater controller 226. The induction heater controller 226includes a processor 227 to perform one or more control functions withrespect to the induction heater 212 and/or the power drive unit 220. Forexample, the induction heater controller 226 generates one or moreinstruction(s) to activate and/or deactivate the induction heater 212and monitors the status and/or performance of the induction heater 212and/or other components of the induction heater control station 210(e.g., the power drive unit 220). The power drive unit 220 providespower to the induction heater controller 226, as represented by arrow228 of FIG. 2.

In the example system 200 of FIG. 2, the induction heater controller 226is communicatively coupled with the processor 204 of the diagnosticinstrument 202. The induction heater controller 226 includes a serialcommunication port to facilitate the transmission of data between theinduction heater controller 226 and the processor 204 of the diagnosticinstrument 202, as represented by arrow 230 of FIG. 2. For example, oneor more user commands received via the GUI(s) 209 of the diagnosticinstrument 202 can be transmitted to the induction heater controller 226via the serial communication port 230. Also, the induction heatercontroller 226 can transmit, for example, performance data generated bymonitoring the induction heater 212 to the diagnostic instrument 202 viathe serial communication port 230. As another example, the timer 211 ofthe diagnostic instrument 202 transmits a trigger signal 232 to theinduction heater controller 226 to provide timing control for one ormore inductive heating events, such as activation and deactivation ofthe induction heater 212.

In addition to receiving power from the power drive unit 220 asdisclosed above, the example induction heater controller 226 of FIG. 2is communicatively coupled with the power drive unit 220. The exampleinduction heater controller 226 provides one or more instructions 234 tothe power drive unit 220 with respect to, for example, activation of theinduction heater 212, a temperature at which to heat the work piece 214,etc. The example power drive unit 220 generates the drive signals 224 todrive the induction heater 212 based on the instruction(s) 234 receivedfrom the induction heater controller 226.

The example induction heater controller 226 also receives data from thepower drive unit 220 with respect to, for example, performance of theinduction heater 212. In the example of FIG. 2, the power drive unit 220communicates data such as a status 236 of the induction heater 212,monitors data with respect to a current and/or a voltage at theinduction heater 212, etc. Based on the data received from the powerdrive unit 220, the induction heater controller 226 can communicate, forexample, a present/ready status signal 240 of the induction heatercontrol station 210, a pass/fail status signal 242 with respect to aperformance state of one or more components of the induction heatercontrol station 210 such as the power drive unit 220 and/or theinduction heater 212, and/or other signals containing data that can beused to control the induction heater control station 210 via thediagnostic instrument 202.

As disclosed below, in some examples, the induction heater controller226 receives feedback 244 from the induction heater 212 with respect to,for example, a frequency at which a circuit of the induction heater 212is oscillating. In some examples, the induction heater controller 226receives analog feedback signals from the power drive unit 220 and/orthe induction heater 212. The induction heater controller 226 convertsthe analog signals to digital data (e.g., via the processor 227) foranalysis by the induction heater controller 226 and/or the processor 204of the diagnostic instrument 202.

The example system 200 of FIG. 2 can include a pump 246 to control theflow of fluid 218 used to clean the work piece 214. Operation of thepump can be controlled by the power drive unit 220 based on, forexample, the instructions 234 received from the processor 227 of theinduction heater controller 227. In other examples, the pump 246 iscontrolled by the processor 204 of the diagnostic instrument 202. Theinstruction(s) can control, for instance, a speed at which the pump 216pumps the fluid 218.

FIG. 3 is a block diagram of the example induction heater controlstation 210 of FIG. 2. The example induction heater control station 210includes a heater board 300 (e.g., a printed circuit board) includingone or more electrical components (e.g., circuits) coupled thereto. Theexample heater board 300 of FIG. 3 is operatively coupled to theinduction heater controller 226.

In some examples, the heater board 300 includes the power drive unit 220(e.g., the power drive unit 220 is mechanically and electrically coupledto the heater board 300). In other examples, the power drive unit 220 isseparate from, but operatively coupled to, the heater board 300. Asdisclosed above, the power drive unit 220 receives power from the powersource 206 of the diagnostic instrument 202 of FIG. 2. The power driveunit 220 delivers power to, for example, the induction heater controller226, the other components of the heater board 300, etc.

The example heater board 300 of FIG. 3 is operatively coupled to theinduction heater 212. The example induction heater 212 of FIG. 3includes a tank circuit board 302 (e.g. a printed circuit board). Insome examples, the tank circuit board 302 and the heater board 300 forma single board. In other examples, the heater board 300 and the tankcircuit board 302 are separate boards.

The example tank circuit board 302 of FIG. 3 includes a tank circuit 304(e.g., an inductance-capacitance or LC circuit) formed by a capacitor306 and an inductor or work coil 308 (e.g., the coil 102 of FIG. 1). Thework coil 308 includes an electrically conductive material such as ametal. The example power drive unit 220 provides electrical current 310to and/or generates a voltage at the tank circuit 304. In some examples,the power drive unit 220 provides the current 310 to the tank circuit304 via, for example, a shielded cable or a coaxial cable. As disclosedabove with respect to FIG. 1, when the electrical current 310 flowsthrough the work coil 308, a magnetic field (e.g., the magnetic field106 of FIG. 1) is generated by the work coil 308. The magnetic field(s)can be used to heat the work piece 214 of FIG. 2 when the work piece 214is disposed proximate to the work coil 308 (e.g., at least partiallydisposed in an opening of the work coil 308).

The example tank circuit board 302 of FIG. 3 includes a sense coil 312.In the example induction heater 212 of FIGS. 2 and 3, the sense coil 312is wound around the work coil 308. The example sense coil 312 detects orsenses the magnetic field(s) generated by the work coil 308. The sensecoil 312 generates one or more sense signals 314 that are transmitted tothe heater board 300. As disclosed below, the sense signal(s) 314generated by the sense coil 312 are detected by frequency controlcircuitry 316 of the heater board 300 to drive the tank circuit 304 at aresonant frequency.

The example tank circuit board 302 includes a coil temperature sensor318. The coil temperature sensor 318 detects a temperature of the workcoil 308 and/or the sense coil 312 during, for example, generation ofthe magnetic field by the work coil 308. The coil temperature sensor 318sends coil temperature data 320 to a temperature monitor 322 of theexample heater board 300. In some examples, the temperature monitor 322also collects temperature data with respect to the temperature of theheater board 300 and/or one or more electrical components of the boardbased on, for example, one or more temperature sensors coupled to theheater board 300. The temperature monitor 322 sends heater temperaturedata 323 with respect to the temperature of the work coil 308, the sensecoil 312, the heater board 300, etc. to the induction heater controller226.

The example heater board 300 of FIG. 3 also includes an electricalcurrent monitor 324. The electrical current monitor 324 generates datawith respect to the electrical current 310 being provided to the tankcircuit 304 such as an amount of the current, a frequency of thecurrent, etc. For example, the electrical current monitor 324 can detectovercurrent, or current exceeding a threshold current to be received bythe tank circuit 304. The electrical current monitor 324 can detectchanges in the current at the induction heater 212. The electricalcurrent monitor 324 generates one or more current signals 325 based onthe detection and transmits the current signal(s) 325 to the inductionheater controller 226.

The example heater board 300 of FIG. 3 includes a voltage monitor 326.The voltage monitor 326 generates data with respect to a voltage in thetank circuit 304. In some examples, the voltage monitor 326 detectsovervoltage, or voltage in the tank circuit 304 that exceeds a thresholdlimit of the tank circuit 304. The voltage monitor 326 can detect thevoltage based on voltage measurements obtained from the tank circuit 304(e.g., via a voltmeter). The electrical voltage monitor 326 can alsodetect changes in the voltage at the induction heater 212. The voltagemonitor 326 generates one or more voltage signals 327 based on thedetection and transmits the voltage signal(s) 327 to the inductionheater controller 226.

As disclosed above, the example heater board 300 includes frequencycontrol circuitry 316. The frequency control circuitry 316 sends one ormore sense coil detection signals 328 to the example induction heatercontroller 226 of FIG. 3 based on the sense signals 314 generated by thesense coil 312 with respect to oscillation of the tank circuit 304. Theexample heater board 300 also includes a fixed frequency clock 330. Asdisclosed below, the frequency control circuitry 316 selectively enablesthe fixed frequency clock 330 to generate one or more fixed frequencysignals or disables the fixed frequency clock 330 based on the sensesignal(s) 314. The fixed frequency signals generated by the fixedfrequency clock 330 cause the current 310 in the tank circuit 304 tooscillate at a fixed frequency.

Thus, the example induction heater controller 226 receives one or moresignals 323, 325, 327, 328 from the circuitry of the example heaterboard 300. The induction heater controller 226 processes the data 323,325, 327, 328 by, for example, converting the data from analog todigital, filtering the data, removing noise from the data, etc. Theexample induction heater controller 226 of FIG. 3 analyzes the datareceived from the heater board 300 and generates one or moreinstructions with respect to operation of the induction heater 212and/or transmits data to the diagnostic instrument 202 of FIG. 2 fordisplay to a user via the GUI(s) 209. Any of the functions of theexample induction heater controller 226 of FIG. 3 disclosed herein canbe performed by the processor 227 associated with the induction heatercontroller 226.

The example induction heater controller 226 of FIG. 3 includes a drivemanager 332. The drive manager 332 generates the instruction(s) 234 thatare transmitted to the power drive unit 220 and that cause the powerdrive unit 220 to generate, for example, the current 310 provided to thetank circuit 304 and/or the voltage to be generated at the tank circuit304. The instruction(s) 234 generated by the drive manager 332 include,for example, an amount of current 310 to be provided to the tank circuit304 and/or a voltage to be generated at the tank circuit 304, a durationfor which the current 310 should be provide, etc. In some examples, thedrive manager 332 generates the instruction(s) 234 based on referencedata 334 stored in a database 336 of the induction heater controller226. The reference data 334 can include data regarding, for example, acurrent threshold and/or a voltage threshold of the tank circuit 304,respective inductances of the work coil 308 and/or the sense coil 312, acapacitance of the capacitor 306, etc.

The example induction heater controller 226 of FIG. 3 includes afrequency manager 338. The frequency manager 338 processes the sensecoil detection signals 328 generated by the frequency control circuitry316. In some examples, the frequency manager 338 generates one or morefrequency instructions 339 with respect to operation of the frequencycontrol circuitry 316 and/or the fixed frequency clock 330 to cause thetank circuit 304 to selectively oscillate at resonant frequency or afixed frequency, as disclosed below.

The example induction heater controller 226 of FIG. 3 includes aperformance manager 340. The electrical current monitor 324 and/or thevoltage monitor 326 send the respective current signal(s) 325 and/or thevoltage signal(s) 327 indicative of, for example, a change in thecurrent and/or the voltage at the induction heater 212 (e.g., at thetank circuit 304) to the performance manager 340. The exampleperformance manager 340 generates one or more instructions for, forexample, the power drive unit based on the monitoring of the currentand/or voltage.

In some examples, the change(s) in voltage and/or current detected atthe induction heater 212 are based on one or more of the properties 215of the work piece 214 of FIG. 2 introduced into the induction heater212. For example, the work piece 214 of FIG. 2 includes the firstportion 217 and the second portion 219 having a diameter smaller thanthe diameter of the first portion 217 first diameter. In some examples,a thickness of a skin of the first portion 217 is greater than athickness of the second portion 219. As disclosed above, the first andsecond portions 217, 219 of the work piece 214 can be selectivelydisposed proximate to the work coil 308 for heating via the magneticfield generated by the current 310 in the work coil 308. The presence ofthe first portion 217 and/or the second portion 219 relative to the workcoil 308 can affect a load on the work coil 308.

In some examples, the electrical current monitor 324 of FIG. 3 detects achange in current at the tank circuit 304 when the second portion 219having the thinner skin is disposed proximate to the work coil 308 ascompared to the when the first portion 217 is disposed proximate to thework coil 308. For example, the electrical current monitor 324 candetect that the current 310 at the tank circuit 304 has dropped when thesecond portion 219 is proximate to the work coil 308 as compared to whenthe first portion 217 is disposed proximate to work coil 308. Theelectrical current monitor 324 generates the current signal(s) 325 withrespect to the change in current at the induction heater 212 (e.g., thedropped current). In some examples, the voltage monitor 326 detects achange in voltage at the tank circuit 304 based on the load change atthe work coil 308 due to the presence of the first portion 217 or thesecond portion 219 proximate to the work coil 308. The voltage monitor326 generates the voltage signal(s) 327 with respect to the change involtage detected at the induction heater 212.

The performance manager 340 of the induction heater controller 226analyzes the current signal(s) 325 and/or the voltage signal(s) 327relative to a temperature profile 342 for the work piece 214 stored inthe database 336 of the example induction heater controller 226 of FIG.3. The temperature profile 342 includes predefined data (e.g., providedvia one or more user inputs to the processor 227 of the induction heatercontroller 226) with respect to a minimum temperature to heat the workpiece 214 over a length of the work piece 214 to, for example, clean orsterilize the work piece 214. The temperature profile 342 is used by theperformance manager 340 to determine power settings over time withrespect to power to be provided to the induction heater 212 relative toone or more portions 217, 219 of the work piece 214 (e.g., loads) beingheated by the induction heater 212.

The temperature profile 342 can be based on, for example, known datawith respect to the properties 215 of the work piece 214 and a responseof the work piece 214 to the magnetic field(s) based on the properties215. The properties 215 of the work piece 214 result in load impedancevariations at the induction heater 212 based on differences in, forexample, skin thickness, diameter, etc., at the different portions 217,219 of the work piece 214. The performance manager 340 uses thetemperature profile 342 to control power delivered to the work piece 214to heat the work piece 214 at each position of the work piece 214relative to the induction heater 212 over time.

In some examples, the temperature profile 342 is a time-based profilewith respect to a temperature at which the one or more portions 217, 219of the work piece 214 are to be heated over time. In some examples, thetemperature profile 342 is generated by the performance manager 340 ofthe induction heater controller 226 based on data previously collectedduring heating of the work piece 214 and/or one or more other workpieces (e.g., calibration or reference data). In some examples, thetemperature profile 342 is based on one or more user inputs received viathe GUI(s) 209 of the diagnostic instrument 202 with respect to, forexample, voltage to be generated at the tank circuit 304 over timerelative to a position of the work piece 214 at the induction heater212. In in some examples, the temperature profile 342 represents anoptimal temperature at which to heat the first portion 217 and/or thesecond portion 219 of the work piece 214 over time.

The example performance manager 340 of FIG. 3 directs to the drivemanager 332 to provide the instruction(s) 234 to the power drive unit220 based on the temperature profile 342. In some examples, theperformance manager 340 determines the instruction(s) 234 to be sent tothe power drive unit 220 based on a start time of the heating of thework piece 214 relative to a starting position of the work piece 214 inthe induction heater 212 (e.g., whether the first portion 217 or thesecond portion 219 is to be heated first). In some examples, theperformance manager 340 determines a position of the work piece 214relative to the work coil 308 based on data from, for example, theprocessor 204 of the diagnostic instrument 202 regarding the movementand/or position of the robotic arm 221 and/or other positional data(e.g., a position data). The performance manager 340 determinesadditional instruction(s) 234 to be sent to the power drive unit 220based on anticipated positions of the work piece 214 relative to theinduction heater 212 as reflected in the temperature profile 342.

The performance manager 340 uses the temperature profile 342 todetermine current and/or power to be provided to and/or the voltage tobe generated at the induction heater 212 at different times during theheating of the work piece 214 at the induction heater 212. In someexamples, the performance manager 340 of FIG. 3 analyzes the currentsignal(s) 325 and/or the voltage signal(s) 327 indicative of changes incurrent and/or voltage at the induction heater 212 relative to thetemperature profile 342. Based on the analysis, the example performancemanager 340 generates the instruction(s) 234 for the power drive unit220 with respect to the current, voltage, and/or power at the inductionheater 212 for different heat settings associated with the temperatureprofile 342.

For example, based on the current signal(s) 327, the performance manager340 can detect a drop in current at the tank circuit 304 due to, forexample, the second portion 219 of the work piece 214 having the thinnerskin being disposed proximate to the work coil 308 as compared to thefirst portion 217 of the work piece 214. The performance manager 340analyzes the temperature profile 342 to determine a higher temperatureis required to heat the second portion 219 as compared to the firstportion 217 due to the thinner skin of the work piece 214 (e.g., due tothinner portion 219 of the work piece heating less efficiently than thethicker portion 217 of the work piece 214). The example performancemanager 340 generates the instruction(s) 234 for the power drive unit220 to increase the current 310 provided to the tank circuit 304 whenthe second portion 219 is disposed proximate to the work 308 as comparedthe first portion 217 of the work piece 214.

In some examples, the DC-DC converter of the power drive unit 220 servesas a power source for generating voltage at the induction heater 212. Insuch example, the temperature profile 342 includes voltage values. Theinstruction(s) 234 sent to the power drive unit 220 include voltages tobe generated at specific time intervals based on the temperature profile342. In such examples, for a given heat setting (e.g., voltage), thepower varies as a load impedance at the tank circuit 304 varies asresult of movement of the work piece 214 between the first and secondportions 217, 219 (e.g., via the robotic arm 221 of FIG. 2).

In other examples, the temperature profile 342 includes power valuesrepresentative of desired power output values (e.g., wattage) atdifferent times. In such examples, the performance manager 340calculates the power based on the current data 325 from the electricalcurrent monitor 324 and the voltage data 327 from the voltage monitor326. The performance manager 340 adjusts the output voltage provided bythe DC-DC converter to obtain the desired output power. In suchexamples, for a given heat setting (e.g., wattage), the power issubstantially constant as the load impedance varies as result ofmovement of the work piece 214 between the first and second portions217, 219 (e.g., via the robotic arm 221 of FIG. 2).

In other examples, the power drive unit 220 includes a fixed voltagesource. In such examples, the output voltage is adjusted by duty cyclesof FET gate signals of the power drive unit 220.

Thus, the example performance manager 340 of FIG. 3 provides for dynamicadjustment of the current and/or voltage at the tank circuit 304 and, asresult, the power provided to the work piece 214 to heat the work piece214. The performance manager 340 accounts for load impedance variationsdue to the properties 215 of the work piece 214 and the position of thework piece 214 relative to the induction heater 212 based on themonitoring of the current by the electrical current monitor 324 and/orthe voltage by the voltage monitor 326. The example performance manager340 uses the temperature profile 342 to respond to dynamic loadvariabilities resulting from the different portions 217, 219 of the workpiece 214 to be heated. The current, voltage, and/or power adjustmentsimplemented via the power drive unit 220 substantially improveperformance of the induction heater 212 in view of the differentproperties 215 of the work piece 214 at different portions 217, 219 toefficiently heat the work piece 214.

The example induction heater controller 226 of FIG. 3 also includes afailure monitor 344. The failure monitor 344 analyzes the temperaturedata 323 generated by the temperature monitor 322 with respect to,example, potential overheating of one or more components of the heaterboard 300 (e.g., the frequency control circuitry 316) and/or theinduction heater 212. The failure monitor 344 analyzes the currentsignal(s) 325 and/or the voltage signal(s) 327 with respect toovercurrent and/or overvoltage that could damage the induction heater212 based, for example, an amount or frequency of the current 310 beingprovided to the tank circuit 304.

Based on the analysis of the temperature, current, and/or voltage data323, 325, 327, the failure monitor 344 predicts whether one or more ofthe components of the induction heater control station 210 are likely tomalfunction and/or fail (e.g., overheat, short). The failure monitor 344can predict a performance status with respect to, for example, theinduction heater 212 based on the reference data 334 stored in thedatabase 336 of the induction heater controller 226. For example, thefailure monitor 344 can detect overcurrent based on a predefined currentthreshold for the tank circuit 304 stored in the database 336.

If the failure monitor 344 determines that one or more components of theinduction heater control station 210 are malfunctioning and/or failingand/or if the failure monitor 344 predicts that the one or morecomponents are likely to fail, the failure monitor 344 generates one ormore failure instructions 346. The failure instructions 346 can include,for example, instructions for the problematic component(s) to shut down,for other components to take over for the problematic component(s), etc.In some examples, the instruction(s) 234 sent to the power drive unit220 include instructions to address potential failure due to, forexample, overcurrent and/or overvoltage at the tank circuit 304 byreducing and/or stopping delivery of current to the tank circuit 304. Insome examples, the failure monitor 344 stores historical data withrespect to performance tracking of the heater board 300 and/or the tankcircuit board 302 in the database 336. The historical data can be usedby the failure monitor 344 to predict component failure.

The failure monitor 344 can also update the present/ready status signal240 and/or the pass/fail status signal 242 (as shown in FIG. 2)transmitted to the processor 204 of the diagnostic instrument 202 basedon analysis of the performance data of the induction heater controlstation 210. For example, if the failure monitor 344 detects an errorwith the induction heater 212, the failure monitor 344 can update thepass/fail status signal 242 to indicate the error state of the inductionheater 212. The failure monitor 344 can generate other warnings fordisplay, via, for example the GUI(s) 209 of the diagnostic instrument202 with respect failure and/or historical data indicating changes inperformance over time that may indicate future failures.

The example induction heater controller 226 of FIG. 3 includes acommunicator 348 to transmit one or more of the instruction(s) 234, 339,346 to the heater board 300. The communicator 348 can also transmit thepresent/ready status signal 240 and/or the pass/fail status signal 242to the processor 204 of the diagnostic instrument 202.

FIG. 4 is a diagram of the example frequency control circuity 316, thefixed frequency clock 330, and the tank circuit 304 of the exampleinduction heater control station 210 of FIG. 3. As disclosed above withrespect to FIG. 3, the tank circuit 304 includes the capacitor 306 andthe work coil or inductor 308. The tank circuit 304 stores energy via anoscillating current between the capacitor 306 and the work coil 308. Theoscillation of the current can result in energy losses in tank circuit304. For example, energy can be lost due to the resistances of the workcoil 308, the resonance of the capacitor 306, and the tank circuit board302. Energy can also be lost as a result of the work piece 214 beingheated by the magnetic field generated by the work coil 308. In theexample of induction heater control station 210 of FIGS. 2-4, energy isprovided to the tank circuit 304 in the form of an alternating currentthat is synchronized with the current already circulating in the tankcircuit 304.

In the example of FIG. 4, the introduction of the work piece 214 in thetank circuit 304 changes an effective inductance of the work coil 308.Also, variations in the properties 215 of the work piece 214 such asdensity and/or a shape (e.g., at the different portions 217, 219) canalso cause changes in the effective inductance of the work coil 308.Changes in effective inductance of the work coil 308 affect the resonantfrequency of the tank circuit 304, or the frequency at which the currentoscillates in the tank circuit 304 with the least energy loss. In theexample of FIG. 4, the alternating current injected into the tankcircuit has a frequency that is varied based on the changing effectiveinductive at the work coil 308 to maximize efficiency with respect tothe synchronization of the current introduced into the tank circuit 304with the current already circulating in the tank circuit 304. Suchfrequency adjustments enable the tank circuit 304 to oscillate at itsresonant frequency and provide a dynamic response to load variations atthe tank circuit 304 due to the introduction and/or manipulation of thework piece 214.

As disclosed above, the tank circuit 304 includes the sense coil 312disposed proximate to (e.g., wound around) the work coil 308. The sensecoil 312 sense the magnetic field generated by the work coil 308 (e.g.,the magnetic field 106 of FIG. 1) and generates the sense signal(s) 314.The sense signal(s) 314 are used to synchronize the alternating current310 that is injected into the tank circuit with current 401 alreadyflowing in the tank circuit 304.

For example, at the beginning of a heat cycle (e.g., when the work piece214 is disposed proximate to the work coil 308), a variable DC powersupply 400 (e.g., of the power drive unit 220) is enabled by, forexample, the instruction(s) 234 from the induction heater controller 226of FIG. 3. The variable DC power supply 400 is set to a low power levelby the drive manager 332 of the induction heater controller 226. The lowpower level setting of the variable DC power supply 400 limits theoscillation of the tank circuit 304 when the tank circuit 304 isoscillating at a frequency that may or may not be its resonantfrequency, thereby limiting energy losses. In other examples, a powerlevel of the variable DC power supply is not adjustable.

In the example of FIG. 4, the fixed frequency clock 330 is enabled bythe example frequency manager 338 of the induction heater controller 226of FIG. 3. The frequency manager 338 sets the fixed frequency clock 330to generate a fixed frequency signal 402 proximate to the resonantfrequency current of the tank circuit 304 (e.g., based on predefineddata). The fixed frequency signal 402 travels via a switch 404 (e.g., asingle pole, double throw or SPDT switch) to a SYNC input pin 406 of aswitched resonant frequency (RF) current drive circuit 408. The fixedfrequency signal 402 causes the current 310 supplied by the variable DCsupply and the current 401 already in the tank circuit 304 to oscillateat a fixed frequency.

The example sense coil 312 of FIG. 4 senses induced oscillating fieldsin the work coil 308 as a result of the current flowing through the workcoil 308 and generates the sense signal(s) 314. The example frequencycontrol circuitry 316 of FIG. 4 includes a signal scaler 410. The signalscaler 410 scales the sense signal(s) 314 relative to the SYNC input pin406 of the switched RF current drive circuit 408 (e.g., voltagescaling). The signal scaler 410 also applies a delay to the sensesignal(s) 314 to optimize current synchronization to generate a scaledsense signal 412. In the example of FIG. 4, the signal scaler 410includes circuitry to detect a validity of the sense signal(s) 314 withrespect to, for example, scaling of the signal to predefined voltages,signal amplitude, etc.

When the signal scaler 410 detects the validity of the sense signal(s)314 the switch 404 (e.g., the SPDT switch) is thrown such that thefrequency control circuitry uses the sense signal(s) 314 to drive theSYNC input pin 406 of the switched RF current drive circuit 408 insteadof the fixed frequency signal 402. As a result, the tank circuit 304 isreleased from being driven by the fixed frequency clock 330 and insteadis driven at its resonant frequency with respect to the current 310provided by the variable DC power supply 400 and the current 401 alreadycirculating in the tank circuit 304.

In the example of FIG. 4, when the tank circuit 304 is driven at itsresonant frequency, the variable DC power supply 400 is adjusted (e.g.,based on instruction(s) 234 from the drive manager 332) to a high powerlevel. Also, when the work piece 214 is disposed proximate to (e.g.,inserted into) the work coil 308, the resonant frequency of the tankcircuit 304 changes as the effective inductance of the work coil 308changes due to the presence of the work piece 214. The sense coil 312generates the sense signal(s) 314, which reflect the (e.g., modified)resonant frequency in the tank circuit 304. As a result, the currentpassing through the switched RF current drive circuit 408 issynchronized with current 401 in the tank circuit 304. Thus, thefrequency control circuity 316 dynamically responds to the introductionof the work piece 214 into the tank circuit 304 to enable the tankcircuit 304 to be driven at its resonant frequency when the work piece214 being heated by the work coil 308. The sense coil 312 and thefrequency control circuitry 316 form a feedback loop that responds tovariabilities in resonant frequency at the induction heater 212.

In the example FIG. 4, driving the tank circuit 304 at its resonantfrequency substantially minimizes energy losses in the tank circuit 304.As a result, more energy is transferred to the work piece 214 to heatthe work piece 214 as compared to if the tank circuit 304 oscillated ata fixed frequency that was not the resonant frequency of the tankcircuit 304. Thus, the self-oscillation of the tank circuit 304 at itsresonant frequency increases an efficiency of the induction heater 212.Also, in allowing the tank circuit 304 to oscillate at its resonantfrequency rather than driving the tank circuit 304 to resonant at afixed frequency, the example frequency control circuitry 316substantially compensates for manufacturing variabilities and/or effectof aging of components of the induction heater control station 210, suchas the work coil 308, the capacitor 306, the circuit boards 300, 302,etc. Manufacturing variabilities and/or age can change the oscillationbehavior of the tank circuit 304 and, thus, result in inefficiencies ifthe tank circuit 304 were driven to oscillate only at a fixed frequency.Further, the example of FIG. 4 dynamically responds to loadvariabilities due to the introduction of the work piece 214 into thetank circuit 304 and/or exposure of different portions 217, 219 of thework piece 214 having different properties 215 to the induction heater212. The example of FIG. 4 accommodates the resulting effects on theeffective impedance of the work coil 308 and the resonant frequency ofthe tank circuit 304 due to the load variabilities by adjusting to themodified resonant frequency.

At the end of the heat cycle, the drive manager 332 of the inductionheater controller 226 adjusts the variable DC power supply 400 to thelow power setting and, after a predefined period of time (e.g., adelay), turns off the variable DC power supply 400. As a result, theenergy in the tank circuit 304 diminishes. Over time, the sense coil 312no longer generates a sense signal 314 large enough to be recognized asvalid by the signal scaler 410. In such examples, the SYNC input pin 406of the switched RF current drive circuit 408 is switched back to bedriven by the fixed frequency clock 330. As a result, any remainingenergy in the tank circuit 304 dissipates. After a predefined period oftime (e.g., a delay), the drive manager 332 sends an instruction 234 forthe fixed frequency clock 330 to be disabled.

FIG. 5 is an example diagram of a temperature profile 500 such as thetemperature profile 342 of FIG. 3 for a work piece 502 having two ormore portions with different properties, such as size, skin thickness,etc. The work piece 502 can be, for example, the work piece 214 of FIG.3. The work piece 502 can include, for example, an aspiration anddispense device.

As illustrated in FIG. 5, the example temperature profile 500 includes aplot of temperature versus time for a first portion 504 of the examplework piece 502 and a second portion 506 of the work piece 502. The firstportion 504 of the work piece 502 can have, for example, a firstthickness and the second portion 506 can have a second thicknessdifferent from the first thickness. The second portion 506 can have oneor more other different properties from the first portion 504, such as adifferent size, cross-sectional shape, etc.

As illustrated in FIG. 5, the example temperature profile 500 includes afirst temperature profile 508 for the first portion 504 withtemperatures to heat the first portion 504 of the work piece 502 overtime when the first portion 504 is disposed proximate to the work coil308. The example temperature profile 500 includes a second temperatureprofile 510 for the second portion 506 with temperatures to heat thesecond portion 506 of the work piece 502 over time when the secondportion 506 is disposed proximate to the work coil 308. In someexamples, the first and second temperature profiles 508, 510 represent,for example, minimum temperatures at which to heat the respective firstand second portion 504, 506 of the work piece 502 to clean (e.g.,sterilize) the work piece 502. In other examples, the first and secondtemperature profiles 508, 510 represent optimal temperatures at which toheat the respective first and second portions 504, 506 to clean (e.g.,sterilize) the work piece 502 in a predetermined time period. Theoptimal temperature data can be based on, for example, data collectedfrom one or more prior inductive heating cycles of the work piece 502and/or other work pieces. In some examples, the performance manager 340of FIG. 3 uses the example temperature profile 500 to generate theinstruction(s) 234 with respect to, for example, the current and/orpower to be provided to and/or a voltage to be generated at the tankcircuit 304 to heat the first and second portions 504, 506 of the workpiece 502 at one or more predefined temperature or heat settings overtime.

FIG. 6 is a perspective view of an example work coil 600 (e.g., theexample work coil 308 of FIG. 3) that may be used with the inductionheater 212 of the example induction heater control station 210 of FIGS.2-4. The example work coil 600 includes a housing 602. In the example ofFIG. 6, the housing 602 is a magnetic concentrator made of, for example,Ferrotron. The housing 602 includes a Litz wire 604 disposed therein.The Litz wire 604 includes a plurality of insulated wire strands woventogether. In some examples, the Litz wire 604 is wrapped around amandrel (e.g., a PEEK™ mandrel).

The example housing 602 of FIG. 6 also includes a magnetic wire 606wound around the Litz wire 604. The magnetic wire 606 can include, forexample, insulated copper wire. In the example of FIG. 6, the magneticwire 606 serves as a sense coil (e.g., the sense coil 312 of FIGS. 3 and4) for sensing a magnetic field generated by the work coil 600. In theexample of FIG. 6, the windings of the Litz wire 604 and the magneticwire 606 are in the same direction.

One or more electrical leads 608 can be coupled to the example work coil600. The leads can be disposed in shrink tubing to protect the leadsfrom the heat generated by the work coil 600. The example work coil 600of FIG. 6 includes a thermistor 610, or a resistor that is used tomeasure a temperature of the housing 602 (e.g., the Ferrotron magneticconcentrator). The data generated by the thermistor 610 can be sent to,for example, the failure monitor 344 of the example induction heatercontroller 226 of FIG. 3.

The example work coil 600 can be selectively designed based on, forexample, space constraints with respect to the induction heater controlstation 210 of the diagnostic instrument 202, a size of one or more workpieces to be heated by the work coil 600, etc. In some examples,variables such as wire cross-section shape, wire metal type, a number ofturns of the wires, turn spacing, a height of work coil 600, a diameterof the work coil 600, a shape of the work coil 600, a resistance of thework coil 600, etc. are selectively chosen based on one or more intendeduses of the work coil 600.

As illustrated in FIG. 6, the example work coil 600 includes an opening612. In operation, a work piece (e.g., the work piece 214 of FIG. 2) isdisposed in the opening 612 to be heated by the magnetic field(s)generated by the example work coil 600 of FIG. 6 when current flowsthrough the work coil 600. Although the work piece does not touch ordoes not substantially touch the example work coil 600 during heating,the example work coil 600 is exposed to biological and/or chemicalmaterial(s) on the work piece. Also, in examples where the work piece iswashed during heating, the example work coil 600 is exposed to washfluid(s) (e.g., the fluid(s) 218 of FIG. 2). In some examples, at leastsome of the wash fluid(s) and/or biological/chemical material(s) maytransfer to the work coil 600. Exposure to the wash fluid(s) and/orbiological/chemical material(s) can corrode the work coil 600, which candamage the work coil 600.

To protect against corrosion, the example work coil 600 includes one ormore coatings 614 applied to the housing 602. The coating(s) 614 caninclude, for example, surface treatment chemicals such as Chemtetall™Oaktite® and/or ceramic coatings (e.g., ceramic coatings made byCerakote™). Thus, the example work coil 600 of FIG. 6 includesprotection against corrosion to increase an operational life of the workcoil 600 and improve reliability of the work coil 600 in view ofexposure to biological and/or chemical materials.

As disclosed above, the example induction heater control station 210 ofFIG. 2 generates heat to clean a work piece, such as an aspiration anddispense device. In some examples, the heat can result in overheating ofone or more components of the induction heater control station 210. Theexample induction heater control station 210 manages heat generated bythe work coil (e.g., the work coil 308, 600 of FIGS. 3 and 6), one ormore printed circuit boards (e.g., the heater board 300, the tankcircuit board 302 of FIG. 3), and/or other electrical components of theprinted circuit boards (e.g., the capacitor 306, the frequency controlcircuitry 316 of FIG. 3) through one or more heat management techniques.The heat management techniques employed by the induction heater controlstation 210 substantially reduce risks of, for example, the work coilshortening and/or waste heat damaging the electrical components of theprinted circuit boards.

For example, FIG. 7 illustrates an example tank circuit board 700 (e.g.,the tank circuit board 302 of FIG. 3) including an electromagneticinterference (EMI) shield 702 and a heat sink 704. The EMI shield 702includes a thermally conductive material (e.g., a metal) thatsubstantially surrounds a work coil 706 (e.g., the work coils 308, 600of FIGS. 2, 6). In some examples, the EMI shield 702 is coated with, forexample, a coating including Teflon™. In some examples, the EMI of, forexample, the induction heater 212 of FIG. 2 can exceed limits orregulations imposed by groups such as Underwriters Laboratories and/orgovernment bodies such as the European Union. The example EMI shield 702substantially reduces the EMI of the induction heater 212 so as tocomply with one or more standards for regulatory approval (e.g., CEcompliance).

The example heat sink 704 of FIG. 7 substantially reduces overheating ofthe work coil 706 and/or the tank circuit board 700 by directing wasteheat away from the work coil 706 and/or the tank circuit board 700. Inthe example of FIG. 7, thermal energy is conducted through theconductors of the work coil 706, such as the Litz wire 604 of FIG. 6(and, in some examples, the magnetic wire 606 of the sense coil of FIG.6) and through one or more copper vias formed in, for example, the tankcircuit board 700. The thermal energy is transferred to the heat sink704. In some examples, thermal energy from the work coil 706 is alsotransferred to the heat sink via the thermally conductive material ofthe EMI shield 702. The example heat sink 704 transfers heat from, forexample, the tank circuit board 700 to the ambient environment. In someexamples, the heat sink transfers the heat to an interior of thediagnostic instrument in which the induction heater control station 210is installed (e.g., the diagnostic instrument 202 of FIG. 2).

In some examples, the induction heater controller 226 of the exampleinduction heater control station 210 of FIG. 2 reduces a duty cycle ofthe induction heater 212 (e.g., via the drive manager 332 and/or theperformance manager 340 of FIG. 2) to manage the generation of wasteheat. For example, the induction heater 212 can be activated so as togenerate heat at a first temperature (e.g., based on the temperatureprofile 342, 500 of FIGS. 3 and 5) at a first power setting (e.g.,watts) for a first predefined period of time, such as 4 seconds. Theinduction heater 212 can also be activated so as to generate heat at asecond temperature at a second power setting (e.g., watts) that ishigher than the first temperature for a second predefined period oftime, such as 2 seconds. Although the first temperature generated overthe first (e.g., longer) period of time and the second temperaturegenerated over the second (e.g., shorter) period of time can both beused to heat the work piece, the lower temperature heat generated overthe first (e.g., longer) period of time can take longer to dissipate. Inthe example of FIG. 7, the induction heater controller 226 instructs theinduction heater 212 to generate heat over the shorter, second period oftime to dissipate heat faster. Thus, the induction heater controller 226reduces the duty cycle of the induction heater to more efficientlymanage waste heat.

Thus, the heat management techniques employed by the induction heatercontrol station 210 substantially reduce the risk of overheating theelectrical components such as the coils, capacitor, etc. and, thus,improve performance of the induction heater control station 210.Further, the EMI shield 702, the heat sink 704, and/or the reduction induty cycle substantially reduce the need for other mechanical modes ofcontrolling and/or removing heat from the induction heater controlstation 210, thereby simplifying design considerations.

FIG. 8 is a top, perspective view of the example tank circuit board 700of FIG. 7 including the work coil 706 disposed in a wash cup 800 (e.g.,the wash cup 216 of FIG. 2). FIG. 9 is a cross-sectional view of theexample wash cup 800 and the work coil 706 taken along the 1-1 line ofFIG. 8 including a work piece 900 (e.g., the work piece 214 of FIG. 2)disposed in the work coil 706. For illustrative purposes, the exampleEMI shield 702 of FIG. 7 is not shown in FIG. 8 or 9.

As disclosed above, in some examples, the work coil 706 is at leastpartially disposed in the wash cup 800 to facilitate, for example,washing of the work piece 900 before, during, and/or after inductiveheating of the work piece 900 by the work coil 706 to help removebiological and/or chemical materials on the work piece 900. The wash cup800 collects wash fluid (e.g., the fluid 218 of FIG. 2) used to rinsethe work piece 900. The example wash cup 800 can include one or moreopenings or sections to accommodate and/or removably secure the workcoil 706, electrical cables coupled to the work coil 706, etc.,proximate to or substantially in the wash cup 800.

As illustrated in FIG. 9, a first portion 902 of the work piece 900 isdisposed in the work coil 706 and is heated by the work coil 706. Asecond portion 904 of the work piece 900 is disposed in the wash cup 800and a third portion 906 of the work piece 900 is not disposed in thewash cup 800. The work piece 900 can be selectively moved relative tothe work coil 706 by, for example, the robotic arm 221 of FIG. 2, whichmay hold the third portion 906 of the work piece 900. As disclosedabove, the induction heater control station 210 selectively adjusts theheat generated by the work coil 706 based on a temperature profile(e.g., the temperature profile 342, 500) to heat the first, second,and/or third portions 902, 904, 906 of the work piece 900 based ondifferent properties of the respective portions, such as skin thickness,cross-section shape, diameter, etc.

Before, during, and/or after heating of the work piece 900, the washbuffer flows over one or more surfaces of the work piece 900 so as towash away biological and/or chemical residue on the work piece 900. Insome examples, the wash buffer flows over external and/or internalsurfaces of the work piece 900.

In some examples, a phase change (e.g., liquid to vapor or gas) occurswith respect to the wash buffer used to clean the work piece duringheating of the work piece due to the heat generated by the work coil706. For instance, the pump 246 of the example system 200 of FIG. 2establishes an elevated pressure to move fluid (e.g., a liquid such asthe fluid 218 of FIG. 2) through the work piece 900, which, in thisexample, may be a probe having an opening extending along a length ofthe probe to receive the fluid. The fluid flow rate provided by the pump246 can be substantially constant flow rate(s) or time-dependent flowrate(s). The elevation in pressure raises a saturation temperature ofthe fluid moving through the work piece 900. As a result of the heatgenerated during inductive heating via the work coil 706, thetemperature of a material of at least a portion the work piece 900(e.g., the portion surrounded by the work coil 706) increases due to theexposure of the work piece 900 to heat. The heat generated by the workcoil 706 conducts through, for example, the walls of the work piece 900(e.g., the probe). The heat is transferred to the fluid flowing throughthe work piece 900. As the work piece 900 is exposed to heat over time,the temperatures of the fluid can rise high enough to reach a saturationtemperature for the fluid. When the fluid reaches its saturationtemperature, a phase change of the fluid passing through the probe canoccur. For example, the fluid passing through the portion of the workpiece 900 disposed in the work coil 706 can undergo a phase change andbecome a saturated liquid-vapor mixture due the transfer of heat fromthe work coil through the walls of the work piece 900 to the fluid. Whenthe fluid flows downstream, or past the region of the work piece 900disposed in the work coil 706, the temperature of the fluid falls belowthe saturation temperature. As a result, the vapor in the liquid-vapormixture condenses back to a liquid phase. Thus, the phase change of thefluid may be temporary based on the flow of fluid relative to the workcoil 706.

When the phase change begins, bubbles form in the fluid moving throughthe work piece 900 (e.g., probe). The bubbles can be formed at or nearthe portion of the work piece 900 disposed in the work coil 706. Thebubbles may be formed temporarily in the heated portion of the workpiece 900 surrounded by the work coil. The formation, movement andcollapse of a bubble locally alters the movement of the fluid passingthrough the work piece 900. The alteration of the movement of the fluiddue to the bubble(s) alters magnitude and direction of shear stress inthe fluid. Some inductive heating examples disclosed herein yield theformation, movement and collapse of a plurality bubbles, resulting in aplurality of (e.g., temporary) spikes in shear stress in the fluid andchanges in shear stress direction that facilitate and/or enhance thecleaning of the work piece 900. Thus, in some examples disclosed herein,cleaning of the work piece 900 includes a combination of elevatedtemperatures and elevated liquid shear stresses. In some examples, thepump 246 of FIG. 2 generates pulsatile flow rates, which results inrepeated drops in pressure to facilitate the phase change(s) and/orbubble effect(s).

As an example, the pump 246 of FIG. 2 may dispense fluid (e.g., liquid)at an average of 1.6 mL/s, which may produce an average pressuredifference of 30 psig in the portion of the work piece 900 within thework coil 706. An example fluid can include a wash buffer includingmostly water. As such, the wash buffer properties can be approximated asthose of pure water. Assuming a 1 atm environment, the saturationtemperature of water under this condition would be 134° C. An exteriorsurface temperature of a portion of the work piece 900 (e.g., the firstportion 217 of the work piece 214 of FIG. 2) after preheating for 0.5seconds at 270 W with 1.6 mL/s of fluid flow may be measured as, forexample, 160° C. Accordingly, an inner surface temperature of the workpiece 900 (e.g., defining an opening in the probe) is 154° C. Thus, theinner surface of the work piece 900 and, therefore, a layer of fluid atthe inner surface is above the saturation temperature of water (and,thus, the wash buffer), which enables the phase change of the fluid.

The example wash cup 800 of FIGS. 8 and 9 can be made of a material thatcan withstand the heat generates by the work coil 706, such as Isoplast™plastic. A shape, size, and/or other design factors of the wash cup 800can be different than illustrated in FIGS. 8 and 9. For example, thedesign of the wash cup 800 can be selected based on the diagnosticinstrument with which the wash cup 800 is to be used, the size of one ormore work pieces to be cleaned, etc.

While an example manner of implementing the example system 200 isillustrated in FIGS. 2-9, one or more of the elements, processes and/ordevices illustrated in FIGS. 2-9 may be combined, divided, re-arranged,omitted, eliminated and/or implemented in any other way. Further, theexample diagnostic instrument 202, the example processors 204, 227, theexample power source 206, the example display 208, the example GUI(s)209, the example timer 211, the example induction heater control station210, the example induction heater 212, the example power drive unit 220,the example induction heater controller 226, the example heater board300, the example tank circuit board 302, the example capacitator 306,the example work coil 308, the example sense coil 312, the examplefrequency control circuitry 316, the example coil temperature sensor318, the example temperature monitor 322, the example electrical currentmonitor 324, the example voltage monitor 326, the example fixedfrequency clock 330, the example drive manager 332, the example database336, the example frequency manager 338, the example performance manager340, the example failure monitor 344, the example communicator 346, theexample variable DC power supply 400, the example switched RF currentdrive circuit 408, the example signal scaler 410 and/or, more generally,the example system 200 of FIGS. 2-9 may be implemented by hardware,software, firmware and/or any combination of hardware, software and/orfirmware. Thus, for example, any of the example diagnostic instrument202, the example processors 204, 227, the example power source 206, theexample display 208, the example GUI(s) 209, the example timer 211, theexample induction heater control station 210, the example inductionheater 212, the example power drive unit 220, the example inductionheater controller 226, the example heater board 300, the example tankcircuit board 302, the example capacitator 306, the example work coil308, the example sense coil 312, the example frequency control circuitry316, the example coil temperature sensor 318, the example temperaturemonitor 322, the example electrical current monitor 324, the examplevoltage monitor 326, the example fixed frequency clock 330, the exampledrive manager 332, the example database 336, the example frequencymanager 338, the example performance manager 340, the example failuremonitor 344, the example communicator 346, the example variable DC powersupply 400, the example switched RF current drive circuit 408, theexample signal scaler 410 and/or, more generally, the example system 200of FIGS. 2-9 could be implemented by one or more analog or digitalcircuit(s), logic circuits, programmable processor(s), applicationspecific integrated circuit(s) (ASIC(s)), programmable logic device(s)(PLD(s)) and/or field programmable logic device(s) (FPLD(s)). Whenreading any of the apparatus or system claims of this patent to cover apurely software and/or firmware implementation, at least one of theexample diagnostic instrument 202, the example processors 204,227, theexample power source 206, the example display 208, the example GUI(s)209, the example timer 211, the example induction heater control station210, the example induction heater 212, the example power drive unit 220,the example induction heater controller 226, the example heater board300, the example tank circuit board 302, the example capacitator 306,the example work coil 308, the example sense coil 312, the examplefrequency control circuitry 316, the example coil temperature sensor318, the example temperature monitor 322, the example electrical currentmonitor 324, the example voltage monitor 326, the example fixedfrequency clock 330, the example drive manager 332, the example database336, the example frequency manager 338, the example performance manager340, the example failure monitor 344, the example communicator 348, theexample variable DC power supply 400, the example switched RF currentdrive circuit 408, the example signal scaler 410 and/or, more generally,the example system 200 of FIGS. 2-9 is/are hereby expressly defined toinclude a tangible computer readable storage device or storage disk suchas a memory, a digital versatile disk (DVD), a compact disk (CD), aBlu-ray disk, etc. storing the software and/or firmware. Further still,the example system 200 of FIGS. 2-9 may include one or more elements,processes and/or devices in addition to, or instead of, thoseillustrated in FIGS. 2-9, and/or may include more than one of any or allof the illustrated elements, processes and devices.

Flowcharts representative of example machine readable instructions forimplementing the example system 200 of FIGS. 2-9 are shown in FIGS. 10and 11. In these examples, the machine readable instructions comprise aprogram for execution by a processor such as the processor 227 shown inthe example processor platform 1200 discussed below in connection withFIG. 12. The program may be embodied in software stored on a tangiblecomputer readable storage medium such as a CD-ROM, a floppy disk, a harddrive, a digital versatile disk (DVD), a Blu-ray disk, or a memoryassociated with the processor 227, but the entire program and/or partsthereof could alternatively be executed by a device other than theprocessor 227 and/or embodied in firmware or dedicated hardware.Further, although the example program is described with reference to theflowchart illustrated in FIGS. 10 and 11 many other methods ofimplementing the example system 200 may alternatively be used. Forexample, the order of execution of the blocks may be changed, and/orsome of the blocks described may be changed, eliminated, or combined.

As mentioned above, the example processes of FIGS. 10 and 11 may beimplemented using coded instructions (e.g., computer and/or machinereadable instructions) stored on a tangible computer readable storagemedium such as a hard disk drive, a flash memory, a read-only memory(ROM), a compact disk (CD), a digital versatile disk (DVD), a cache, arandom-access memory (RAM) and/or any other storage device or storagedisk in which information is stored for any duration (e.g., for extendedtime periods, permanently, for brief instances, for temporarilybuffering, and/or for caching of the information). As used herein, theterm tangible computer readable storage medium is expressly defined toinclude any type of computer readable storage device and/or storage diskand to exclude propagating signals and to exclude transmission media. Asused herein, “tangible computer readable storage medium” and “tangiblemachine readable storage medium” are used interchangeably. Additionallyor alternatively, the example processes of FIGS. 10 and 11 may beimplemented using coded instructions (e.g., computer and/or machinereadable instructions) stored on a non-transitory computer and/ormachine readable medium such as a hard disk drive, a flash memory, aread-only memory, a compact disk, a digital versatile disk, a cache, arandom-access memory and/or any other storage device or storage disk inwhich information is stored for any duration (e.g., for extended timeperiods, permanently, for brief instances, for temporarily buffering,and/or for caching of the information). As used herein, the termnon-transitory computer readable medium is expressly defined to includeany type of computer readable storage device and/or storage disk and toexclude propagating signals and to exclude transmission media. As usedherein, when the phrase “at least” is used as the transition term in apreamble of a claim, it is open-ended in the same manner as the term“comprising” is open ended.

FIG. 10 depicts an example flow diagram representative of an examplemethod 1000 for causing a tank circuit of an induction heater such asthe tank circuit 304 of the induction heater 212 of FIGS. 2 and 3 toresonate at a resonant frequency during a heat cycle of the inductionheater. The example method 1000 may be implemented by, for example, theinduction heater controller 226 of FIGS. 2 and 3 (e.g., the processor227), the frequency control circuitry 316 of FIGS. 3 and 4, etc.

The example method 1000 includes setting a variable DC power supply to afirst power setting at a start of a heat cycle (block 1002). The startof the heat cycle can include when a work piece such as the work piece214 of FIG. 2 is disposed proximate to the work coil for heating. Insome examples, the start of the heat cycle is determined based on one ormore user inputs to the induction heater controller 226. The drivemanager 332 of the example induction heater controller 226 of FIG. 3 cansend instruction(s) 234 to the power drive unit 220 to set the variableDC power supply 400 of FIG. 4 to a low power setting to substantiallylimit energy losses at the tank circuit 304 whether or not the tankcircuit 304 is resonating at its resonant frequency.

The example method 1000 includes enabling a fixed frequency clock (block1004). For example, the fixed frequency clock 330 can be enabled by theexample frequency manager 338 of the example induction heater controller226 of FIG. 3. Enabling the fixed frequency clock 330 generates thefixed frequency signal 402, which travels to the SYNC input pin 406 ofthe switched RF current drive circuit 408. The example switched RFcurrent drive circuit 408 drives the tank circuit 304 to oscillate at afixed frequency.

The example method 1000 includes detecting a sense signal (block 1006).For example, when current flows through the work coil 308 of FIG. 3, thework coil 308 generates a magnetic field (e.g., the magnetic field 106of FIG. 1). The example sense coil 312 of FIG. 3 detects the magneticfield and generates the sense signal 314. The sense signal 314 can bedetected by the example signal scaler 410 of the frequency controlcircuitry 316 of FIG. 4.

If the sense signal 314 is not detected, the example method 1000continues with driving the tank circuit 304 to resonate at a fixedfrequency via the current provided to the tank circuit 304 (e.g., block1004). If the signal scaler 410 detects the sense signal 314, theexample method 1000 continues with switching to drive the tank circuitto resonate at its resonant frequency via a scaled sense signal (block1008).

For example, the signal scaler 410 generates the scaled sense signal 412by scaling the sense signal 314 relative to SYNC input pin 406 (e.g.,voltage scaling). The signal scaler 410 applies a delay to the sensesignal 314 to optimize the synchronization of the current provided tothe tank circuit 304 and the current 401 already flowing through thetank circuit 304. In the example method 1000, the frequency manager 338instructs the frequency control circuitry 316 to throw a switch (e.g.,the SPDT switch 404 of FIG. 4) to use the scaled sense signal 412 todrive the switched RF current drive circuit 408 instead of the fixedfrequency signal 402.

The example method 1000 includes setting the variable DC power supply toa second power setting (block 1010). For example, the drive manager 332of the example induction heater controller 226 of FIG. 3 can sendinstruction(s) 234 to the power drive unit 220 to set the variable DCpower supply 400 of FIG. 4 to a high power setting (as compared to thelow setting set at block 1002).

The example method 1000 continues with enabling the tank circuit 304 toresonate at its resonant frequency until a determination is made thatthe heat cycle has ended (block 1012). In some examples, the examplemethod 1000 adjusts the current provided to the tank circuit 304 basedon the sense signal(s) 314 generated during inductive heating of thework piece 214 to enable to the tank circuit 304 to continue to resonateat its resonant frequency despite load variabilities at the work coil308 due to the work piece 214.

In some examples, the induction heater controller 226 determines thatthe heat cycle is to end based on the current signal(s) 325 receivedfrom the electrical current monitor 324 indicating a change in currentflow at the work coil 308. In some examples, changes in current flow atthe work coil 308 can indicate that the work piece 214 or a portionthereof has been moved out of the magnetic field. In some examples, theinduction heater controller 226 determines that the heat cycle is to endbased on one or more user inputs.

If the heat cycle is to end, the example method 1000 includes settingthe setting a variable DC power supply to the first (e.g., low) powersetting (e.g., via the drive manager 332) (block 1014). After a delay,the example method 1000 includes turning off the variable DC powersupply (block 1016).

The example method 1000 of FIG. 10 includes a determination of whetherthe sense signal is detected (block 1018). For example, after thevariable DC power supply is turned off, the energy in the tank circuit304 dissipates over time and the sense coil 312 no longer generatessense signal(s) 314 that are recognized by the signal scaler 410. If thesense signal(s) 314 are no longer detect, the example method 1000includes switching the SYNC input pin 406 of the switched RF currentdrive circuit 408 to be driven by the fixed frequency clock 330 (e.g.,via the drive manager 332) (block 1020). After a period of time, theexample method 1000 includes disabling the fixed frequency clock 330 toend the heat cycle of the induction heater 212 (block 1022).

FIG. 11 depicts an example flow diagram representative of an examplemethod 1100 for inductively heating a work piece such as the work piece214, 502 of FIGS. 2 and 5 via an induction heater, such as the inductionheater 212 of FIG. 2. The example method 1100 may be implemented by, forexample, the induction heater controller 226 of FIGS. 2 and 3 (e.g., theprocessor 227).

The example method 1100 of FIG. 11 begins at the start of a heat cycle,which may be determined by, for example, a user input to the inductionheater controller 226. The user input to begin the heat cycle can causethe drive manager 332 to instruct the power drive unit 220 to provide,for example, current to the tank circuit 304 of the example inductionheater 212.

The example method 1100 includes identifying a temperature profile for aportion of a work piece to be heated (block 1102). For example, theperformance manager 340 of the induction heater controller 226 canidentify the temperature profile 342, 500 stored in the database 336 ofFIG. 3. The example temperature profile 342, 500 includes one or moreheat settings for the induction heater 212 with respect to the portion217, 219, 504, 506 of the work piece 214, 502 to be heated. In someexamples, the performance manager 340 identifies the temperature profile342, 500 for the portion based on one or more user inputs defining, forexample, the properties 215 of the portion 217, 219, 504, 506 to beheated (e.g., size, skin thickness). In other examples, the performancemanager 340 identifies the temperature profile 342 based on a positionof the work piece 214, 502 relative to the induction heater 212 (e.g.,based on movement by the robotic arm 221 of the diagnostic instrument202). In other examples, the performance manager 340 identifies thetemperature profile 342, 500 based on change in current and/or voltageat the induction heater 212 as respectively detected by the electricalcurrent monitor 324 and/or the voltage monitor 326. In some suchexamples, changes such as drop in current can indicate that a differentportion 217, 219, 504, 506 of the work piece 214, 502 is disposedproximate to the work coil 308 for heating.

The example method 1100 includes adjusting a resonance frequency at atank circuit of the induction heater (block 1104). The adjusting of theresonance frequency of the tank circuit can be performed substantiallyas disclosed above with respect to the example method 1000 of FIG. 10.For example, as disclosed above, the induction heater controller 226 andthe frequency control circuitry 316 enable the tank circuit 304 toresonate at its resonant frequency during generation of the magneticfield by the work coil 308 based on sense signal(s) 314 generated by thesense coil 312. The oscillation of the tank circuit 304 at its resonantfrequency provides for efficient transfer of heat to the work piece 214,502.

The example method 1100 includes heating the portion of the work piecebased on the temperature profile (block 1106). For example, theinduction heater 212 of the FIGS. 2-4 can heat the portion 217, 219,504, 506 of the work piece 214, 502 for a predefined duration of time atone or more heat settings based on the temperature profile 342, 500. Insome examples, the induction heater controller 226 generates theinstruction(s) 234 to adjust a current and/or power provided to the tankcircuit 304 and/or a voltage generated at the tank circuit 304 achievethe heat settings of the temperature profile 342, 500 for the portion217, 219, 504, 506 to be heated.

The example method 1100 includes monitoring one or more conditions atthe induction heater (block 1108). For example, the example failuremonitor 344 analyzes the temperature data 323 received from thetemperature monitor 322, the current data 325 received from theelectrical current monitor 324, and/or the voltage data 327 receivedfrom the voltage monitor 326 of FIG. 3. Based on the analysis, theexample failure monitor 344 detects if any of the components of theinduction heater 212 have failed and/or predicts if any of thecomponents are likely to fail. For example, the failure monitor 344identifies conditions that may result in, for example, overheating ofthe work coil 308, shorting of one or more components of the frequencycontrol circuitry 316, etc. In some examples, the failure monitor 344compares the data 323, 325, 327 to reference data 334 stored in thedatabase 336 of FIG. 3 with respect to, for example, threshold currentsand/or voltage for the tank circuit 304. The failure monitor 344 tracksperformance data obtained from the induction heater 212 to identifyand/or predict one or more failures at the induction heater controlstation 210.

The example method 1100 includes generating one or more induction statusupdates (block 1110). For example, the failure monitor 344 can generateone or more instructions 346 to stop operation of the induction heater212 if the failure monitor 344 predicts that the work coil 308 is likelyto overheat. In some examples, the failure monitor 344 instructs thepower drive unit 220 to adjust the current provided to the inductionheater 212 in view of the failure predictions and/or performancetracking by the failure monitor 344. In some examples, the failuremonitor 344 generates the present/ready data 240 and/or the pass/faildata 242 for display via the GUI(s) 209 of the example diagnosticinstrument 202 based on the predictions.

The example method 1100 includes a determination of whether anotherportion of the work piece is to be heated (block 1112). If anotherportion of the work coil is to be heated, the example method 1100returns to identifying the temperature profile 342, 500 for the otherportion to be heated (e.g., block 1102). The example method 1100 adjuststhe resonance frequency at the tank circuit based on changes to theresonant frequency due to load variabilities at the tank circuit toefficiently heat the portion(s) of the work piece (e.g., blocks 1104,1106). The load variabilities can result from the introduction of theother portion into the tank circuit having one or more differentproperties than the portion previously being heated by the inductionheater. If another portion of the work piece is not to be heated, thenthe example method 1100 ends.

FIG. 12 is a block diagram of an example processor platform 1200 capableof executing the instructions of FIGS. 10 and 11 to implement theexample system 200 of FIGS. 2-9. The processor platform 1200 can be, forexample, a server, a personal computer, a mobile device (e.g., a cellphone, a smart phone, a tablet such as an iPad™), a personal digitalassistant (PDA), an Internet appliance, the medical diagnosticinstrument 202 or any other type of computing device.

The processor platform 1200 of the illustrated example includes theprocessor 227. The processor 227 of the illustrated example is hardware.For example, the processor 227 can be implemented by one or moreintegrated circuits, logic circuits, microprocessors or controllers fromany desired family or manufacturer.

The processor 227 of the illustrated example includes a local memory1213 (e.g., a cache). The processor 227 of the illustrated example is incommunication with a main memory including a volatile memory 1214 and anon-volatile memory 1216 via a bus 1218. The volatile memory 1214 may beimplemented by Synchronous Dynamic Random Access Memory (SDRAM), DynamicRandom Access Memory (DRAM), RAMBUS Dynamic Random Access Memory (RDRAM)and/or any other type of random access memory device. The non-volatilememory 1216 may be implemented by flash memory and/or any other desiredtype of memory device. Access to the main memory 1214, 1216 iscontrolled by a memory controller.

The processor platform 1200 of the illustrated example also includes aninterface circuit 1220. The interface circuit 1220 may be implemented byany type of interface standard, such as an Ethernet interface, auniversal serial bus (USB), and/or a PCI express interface.

In the illustrated example, one or more input devices 1222 are connectedto the interface circuit 1220. The input device(s) 1222 permit(s) a userto enter data and commands into the processor 227. The input device(s)can be implemented by, for example, an audio sensor, a microphone, acamera (still or video), a keyboard, a button, a mouse, a touchscreen, atrack-pad, a trackball, isopoint, a voice recognition system, and/or themedical diagnostic instrument 202.

One or more output devices 1224 are also connected to the interfacecircuit 1220 of the illustrated example. The output devices 1224 can beimplemented, for example, by display devices (e.g., a light emittingdiode (LED), an organic light emitting diode (OLED), a liquid crystaldisplay, a cathode ray tube display (CRT), a touchscreen, a tactileoutput device, a printer and/or speakers), the power drive unit 220, thefrequency control circuitry 316, the induction heater 212. The interfacecircuit 1220 of the illustrated example, thus, typically includes agraphics driver card, a graphics driver chip or a graphics driverprocessor.

The interface circuit 1220 of the illustrated example also includes acommunication device such as a transmitter, a receiver, a transceiver, amodem and/or network interface card to facilitate exchange of data withexternal machines (e.g., computing devices of any kind) via a network1226 (e.g., an Ethernet connection, a digital subscriber line (DSL), atelephone line, coaxial cable, a cellular telephone system, etc.).

The processor platform 1200 of the illustrated example also includes oneor more mass storage devices 1228 for storing software and/or data.Examples of such mass storage devices 1228 include floppy disk drives,hard drive disks, compact disk drives, Blu-ray disk drives, RAIDsystems, and digital versatile

Coded instructions 1232 to implement the example methods of FIGS. 10 and11 may be stored in the mass storage device 1228, in the volatile memory1214, in the non-volatile memory 1216, and/or on a removable tangiblecomputer readable storage medium such as a CD or DVD.

From the foregoing, it will be appreciated that the above systems,methods, and apparatus provide for control and monitoring of performanceof an induction heater to reduce biological carryover by one or morework pieces (e.g., probes) via inductive heating. Examples disclosedherein account for manufacturing variabilities and/or aging ofelectrical components of the induction heater by enabling the tankcircuit to resonate at its resonant frequency rather than a fixedfrequency. Further, examples disclosed herein dynamically response toload variabilities at the induction heater due to, for example, theintroduction of the work piece into the induction heater, positioning ofthe work piece relative to the induction heater, and properties ofdifferent portions of the work piece to be heated. Some such examplesadjust current provided to the tank circuit of the induction heater torespond to changes in the resonant frequency of the tank circuit as aresult of the presence of the work piece. Some disclosed examplesprovide for improved reliability of the induction heater through wasteheat management techniques that reduce the risk of overheating and/orthrough predictive failure analysis. Examples disclosed herein can beimplemented with a diagnostic instrument (e.g., a chemical analyzer) toprovide a system that efficiently analyzes samples and convenientlycleans tools used to perform the analysis without requiring a separatecleaning instrument.

Although certain example methods, apparatus and articles of manufacturehave been disclosed herein, the scope of coverage of this patent is notlimited thereto. On the contrary, this patent covers all methods,apparatus and articles of manufacture fairly falling within the scope ofthe claims of this patent.

What is claimed is:
 1. A system comprising: an induction heaterincluding a tank circuit, the tank circuit including a work coil and asense coil, the sense coil to detect a magnetic field generated by thework coil and output a signal in response to the detection; and acontroller to drive the tank circuit to selectively oscillate between afixed frequency and a resonant frequency for the tank circuit toinductively heat a work piece disposed proximate to the tank circuit,the controller to drive the tank circuit to oscillate at the resonantfrequency in response to the signal output by the sense coil.
 2. Thesystem of claim 1, wherein the controller is to drive the tank circuitto selectively oscillate at the resonant frequency based on a propertyof the work piece.
 3. The system of claim 1, wherein the sense coil iswound around the work coil.
 4. The system of claim 1, further includinga heat sink coupled to the induction heater.
 5. The system of claim 1,further including a shield including a thermally conductive materialcoupled to the induction heater.
 6. The system of claim 1, furtherincluding a wash cup, the work coil disposed in the wash cup.
 7. Thesystem of claim 6, wherein the work piece is to be exposed to a fluidduring the inductive heating.
 8. The system of claim 7, wherein thefluid is to undergo a phase change during the inductive heating.
 9. Thesystem of claim 1, wherein the controller is to: access at least one oftemperature data, current data, or voltage data from the inductionheater; and predict a performance condition of the induction heaterbased on the at least one of the temperature data, the current data, orthe voltage data.
 10. The system of claim 1, wherein the work pieceincludes a first portion and a second portion, the controller toselectively adjust a heat setting at the tank circuit for the firstportion and the second portion.
 11. The system of claim 10, wherein thecontroller is to: detect a first current at the tank circuit when thefirst portion of the work piece is proximate to the work coil; detect asecond current at the tank circuit when the second portion of the workpiece is proximate to the work coil, the second current different thanthe first current; identify a current change based on the first currentand the second current; and selectively adjust the heat setting inresponse to the current change.
 12. The system of claim 10, wherein thecontroller is to adjust the heat setting for the first portion based ona first temperature profile for the first portion and adjust the heatsetting for the second portion based on a second temperature profile forthe second portion.
 13. The system of claim 1, further including aswitch to control the oscillation of the tank circuit at the resonantfrequency or the fixed frequency.
 14. The system of claim 1, furtherincluding a sensor to detect a temperature of at least one of the workcoil or the sense coil.
 15. The system of claim 1, further including: asignal scaler to perform a comparison of the signal generated by thesense coil relative to a threshold signal amplitude; and a switch tocontrol oscillation of the tank circuit based on one of the signalgenerated by the sense coil or a signal generated by a fixed frequencyclock in response to the comparison.
 16. The system of claim 1, whereinthe work coil includes a corrosive-resistant coating.
 17. The system ofclaim 1, wherein the controller is to: determine a power output at theinduction heater based on based on voltage data and current data for theinduction heater; perform a comparison of the power output to athreshold; and modify one or more of a voltage or a current provided tothe induction heater to adjust the power output in response to thecomparison.
 18. The system of claim 1, wherein the controller is toinstruct the induction heater to generate a first temperature or asecond temperature based on a duty cycle for the induction heater.